Metabolic engineering is crucial in the development of production strains for platform chemicals, pharmaceuticals and biomaterials from renewable resources. The central carbon metabolism (CCM) of heterotrophs plays an essential role in the conversion of biomass to the cellular building blocks required for growth. Yet, engineering the CCM ultimately aims toward a maximization of flux toward products of interest. The most abundant dissimilative carbohydrate pathways amongst prokaryotes (and eukaryotes) are the Embden-Meyerhof-Parnas (EMP) and the Entner-Doudoroff (ED) pathways, which build the basics for heterotrophic metabolic chassis strains. Although the EMP is regarded as the textbook example of a carbohydrate pathway owing to its central role in production strains like Escherichia coli, Saccharomyces cerevisiae and Bacillus subtilis, it is either modified, complemented or even replaced by alternative carbohydrate pathways in different organisms. The ED pathway also plays key roles in biotechnological relevant bacteria, like Zymomonas mobilis and Pseudomonas putida, and its importance was recently discovered in photoautotrophs and marine microorganisms. In contrast to the EMP, the ED pathway and its variations are not evolutionary optimized for high ATP production and it differs in key principles such as protein cost, energetics and thermodynamics, which can be exploited in the construction of unique metabolic designs. Single ED pathway enzymes and complete ED pathway modules have been used to rewire carbon metabolisms in production strains and for the construction of cell-free enzymatic pathways. This review focuses on the differences of the ED and EMP pathways including their variations and discusses the use of alternative pathway strategies for in vivo and cell-free metabolic engineering.

代谢工程学对于从可再生资源开发平台化学品，药品和生物材料的生产菌株至关重要。异养生物的中央碳代谢（CCM）在生物质向生长所需的细胞构件的转化中起重要作用。然而，设计CCM最终旨在最大程度地提高感兴趣产品的通量。原核生物（和真核生物）中最丰富的异化碳水化合物途径是Embden-Meyerhof-Parnas（EMP）和Entner-Doudoroff（ED）途径，它们为异养代谢底物菌株奠定了基础。尽管EMP由于其在生产菌株（如大肠杆菌）中的重要作用而被视为碳水化合物途径的教科书示例，酿酒酵母和枯草芽孢杆菌在不同生物体中被修饰，补充或什至被其他碳水化合物途径取代。ED途径在生物技术相关细菌中也起着关键作用，例如运动发酵单胞菌和恶臭假单胞菌，其重要性最近在光自养生物和海洋微生物中被发现。与EMP相比，ED途径及其变化并不是为提高ATP产量而经过进化优化的，并且在蛋白质成本，能量学和热力学等关键原理方面存在差异，这些原理可用于构建独特的代谢设计。单一的ED途径酶和完整的ED途径模块已用于重新连接生产菌株中的碳代谢，并用于构建无细胞的酶促途径。这篇综述着重于ED和EMP途径的差异，包括它们的变化，并讨论了在体内和无细胞代谢工程中替代途径策略的应用。